On Mon, Oct 19, 2026 at 07:17:15AM -0300, Leonardo Costa wrote: > From: Leonardo Costa <[email protected]> > > Some simple bridges, such as a resistor ladder DAC, may include a > data-enable input that must be driven at a specific polarity. > > Read the data-enable-active property from the input endpoint and fill > the bridge's input bus flags accordingly, so the upstream encoder drives > DE with the required polarity. The property is applied only if the > bridge doesn't provide its own timings struct. > > Signed-off-by: Leonardo Costa <[email protected]> > ---
Reviewed-by: Frank Li <[email protected]> > drivers/gpu/drm/bridge/simple-bridge.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/simple-bridge.c > b/drivers/gpu/drm/bridge/simple-bridge.c > index 848c2df2a276..c5301295658a 100644 > --- a/drivers/gpu/drm/bridge/simple-bridge.c > +++ b/drivers/gpu/drm/bridge/simple-bridge.c > @@ -183,6 +183,9 @@ static int simple_bridge_probe(struct platform_device > *pdev) > { > struct simple_bridge *sbridge; > struct device_node *remote; > + struct device_node *ep; > + bool de_present; > + u32 de; > > sbridge = devm_drm_bridge_alloc(&pdev->dev, struct simple_bridge, > bridge, &simple_bridge_bridge_funcs); > @@ -220,10 +223,26 @@ static int simple_bridge_probe(struct platform_device > *pdev) > return dev_err_probe(&pdev->dev, PTR_ERR(sbridge->enable), > "Unable to retrieve enable GPIO\n"); > > - /* Register the bridge. */ > sbridge->bridge.of_node = pdev->dev.of_node; > sbridge->bridge.timings = sbridge->info->timings; > > + ep = of_graph_get_endpoint_by_regs(pdev->dev.of_node, 0, -1); > + de_present = !of_property_read_u32(ep, "data-enable-active", &de); > + of_node_put(ep); > + > + if (de_present && !sbridge->bridge.timings) { > + struct drm_bridge_timings *timings; > + > + timings = devm_kzalloc(&pdev->dev, sizeof(*timings), > GFP_KERNEL); > + if (!timings) > + return -ENOMEM; > + > + timings->input_bus_flags = de ? DRM_BUS_FLAG_DE_HIGH : > + DRM_BUS_FLAG_DE_LOW; > + sbridge->bridge.timings = timings; > + } > + > + /* Register the bridge. */ > return devm_drm_bridge_add(&pdev->dev, &sbridge->bridge); > } > > > -- > 2.43.0 > >
